Product Description

Many builders like to use the Sonnax SmarTech drum in some of their 68RFE builds. Over time, builders have also found that the clutch setup provided in the off the shelf kit tends to squawk and even worse, dig into the factory inner drum assembly. Some builders have also tried to increase clutch count by running clutches upside down. This practice causes the first clutch to only get partial apply and leads to premature failures as well as cooling issues due to the change in oil dispersion. Furthermore, in order to run 16 clutches upside down, the UD/OD pressure plate must be machined down. This plate is already thinner out of the box when compared to the factory plate. Machining it even more leads to warpage and a non-flat apply surface. Lastly, the off the shelf kit requires a ring to be pressed on and staked in order to convert the factory inner drum to work with the billet outer drum. This area is prone to leakage and can damaged during installation of the ring.

The RevMax 700S inner drum assembly fixes all of these complaints and adds additional clutch capacity. Our drum requires no adapter ring to be installed as the drum is machined to match the Sonnax drum perfectly. Using this drum allows the builders to run 16 single side OD clutches in the factory direction (facing up). The RevMax inner drum is coated with a Mil-Spec hard coat anodizing that resists steel impregnation. The drum can be built using factory full thickness UD/OD pressure plates or our billet UD/OD pressure plates. In order to use this drum with a factory input hub, you will need machine .040” off the bearing face, please see instructions for more detail. This drum will NOT work with a factory OD drum!

Design Upgrades:

  • Hard Mil-Spec anodized surface
  • Allows up to 16 frictions in the OD clutch while keeping correct clutch facing
  • Drop in design, no adapter ring needed with the Sonnax OD drum*
  • Allows full thickness UD/OD pressure plate to be used with increased clutch counts.

Prevents or Eliminates:

  • Inner drum damage from steel plates impregnating the surface
  • Erratic actual line pressure due to leaks in the OD clutch circuit
  • Unexplained Overdrive Clutch failure
  • Unexplained Underdrive Clutch failure
  • Increased transmission operating temperatures